At least some known bag structures are fabricated from a single ply of material or from multiple plies or layers. The bag structures may be fabricated from paper or plastic materials. Typically, multiwall bags are fabricated as tubes formed from a plurality of paper plies. In addition to having paper plies, one or more plies, typically the innermost one or more plies, may be fabricated from a thin plastic material, or may be coated with a resinous material, to provide a degree of moisture resistance to the finished bag.
Closure of the multiwall bag structures typically is accomplished by applying adhesive (e.g., hot melt or sonically activatable adhesive) to the outer surface of the bag and folding over the top end. Closing the bag by simply folding and adhesively affixing the flap provides a pointed, pinch bottom closure. The opposite end of the bag may be likewise provided with a pinch bottom closure, or it may be closed and sealed in a different configuration, such as a diamond or rectangular configuration, so that the pinch “bottom” may actually be the top of the bag, as may be found commonly in bags containing dry granular material, like dog food, cat litter, or fertilizer. When such a bag is closed and sealed, the folded over closure is typically quite strong, and requires cutting of the bag plies below the folded over and sealed closure in order to gain access to the contents of the bag. Moreover, once such bags are opened, the bags cannot be reclosed or resealed. As such, the contents of the bag may spoil quickly and are susceptible to spillage through the opening or the entering of small pests through the opening.
In order to facilitate opening and closing of bag structures, such as flexible bags, some bag structures are known that incorporate a zipper that may be opened and closed. At least some of these known bag structures also include a slider to aide in opening and closing of the zipper. However, these known bag structures are typically included on flexible bags and bags that are top loaded. When a bag is top loaded, the product loaded into the bag does not contact the zipper during loading. As a result, the zipper is protected from any impact of loading the product into the bag. However, other known bag structures are bottom loaded, such as bags loaded with dry granular material, like dog food, cat litter, or fertilizer. Because these bags are bottom loaded, the zipper at the mouth of the bag is susceptible to damage or rupture during loading of the product into the bag.
In addition, bags having gusseted sides with an opening and closing zipper attached to the top of the bag are oftentimes plagued with ingress channels or openings that allow small pests or insects to enter the bag and contaminate the contents thereof. Accordingly, it would be beneficial to provide a bag having gusseted side walls and an opening and closing zipper that includes sealed areas that facilitate reducing such ingress channels. It would also be beneficial to provide a bag having an opening and closing zipper that is bottom loaded that provides protection against damage to the zipper from loading, and provides tamper resistance.